A Bay Area congressman is calling for a moratorium on federal land swaps after a government report found that the deals, designed to improve wilderness and recreation areas, are wasting millions of taxpayer dollars.

The report by the U.S. General Accounting Office concluded that developers, timber companies and other business interests benefit at the public's expense from deals that are supposed to help protect important natural resource areas.

"Land deals are being cut behind closed doors with tremendous special-interest pressure and limited public input," said Rep. George Miller, D-Martinez. "The taxpayer is getting ripped off."

The U.S. Forest Service and the Bureau of Land Management often exchange land to obtain desirable property near federal parks and wilderness areas. Sometimes, federal officials say, private landowners won't sell unless they get land in return.

Under federal regulations, lands that are exchanged should be of similar market values. But the GAO report documented several instances where private owners made windfall profits on land they purchased from the government.

The federal Bureau of Land Management sold one 70 acre Nevada parcel of land at $763,000. Its buyer turned around and sold it for $4.6 million the same day. The GAO said the case was investigated by the Interior's Office of the Inspector General.

At the same time, federal agencies overvalued property the government received in some exchanges. The land management bureau acquired 47 acres of land at Zephyr Cove, Lake Tahoe for a value of $38 million, the report said. Auditors later determined the land was worth $10 million less.

But questioning appraisals after the fact "is a little like armchair quarterbacking," said David McIlnay, who oversees the Bureau's land swaps in California. "We are taking steps to ensure there is more oversight, in particular if it's land evaluated at more than $500,000."

The GAO examined 51 exchanges, mostly in the western United States. That's just a fraction of the over 2,000 exchanges the two U.S. agencies have made since 1989. Altogether, the agencies acquired 1 million acres from land exchanges during that period, valued at over $1 billion, the GAO said.

The GAO report suggests the Congress may wish to consider directing the federal agencies to discontinue their land exchange programs.

A moratorium would affect California land swaps planned in Cache Creek, the Santa Rosa mountains, the Big Sur coast, and deserts and forests in Southern California, federal officials said.